Quick-acting switch having movable contact means pivotally mounted adjacent the input contact



J1me 1965 L. G. HORWITT ETAL 3,192,343

QUICK-ACTING SWITCH HAVING MOVABLE CONTACT MEANS PIVOTALLY MOUNTED ADJACENT THE INPUT CONTACT Filed May 1, 1962 INVENTQR; Laurence 6. 116mm ff fl 270/2405 Ys United States Patent 3,192,343 QUICK-ACTIN G SWHTCH HAVING MOVABLE CON TACT MEANS PIVQIBTALLY MOUNTED ADJA- CENT THE INPUT CONTACT Laurence G. Horwitt, New Haven, and Vincent Gerald Krenke, Bridgeport, Comm, assignors to The Casco Products Corporation, Bridgeport, 'Conn., a corporation of Connecticut Filed May 1, 1962, Ser. No. 191,473 o'Claims. (Cl.20tl--113) This invention relates to heat-responsive, quick-acting switches particularly adapted for use with electric cigar incandescence for use. When this occurs the igniter plug is automatically returned to open-circuit position ready for removal for use.

If the igniter plug does not return to open-circuit positoo long, and cause a fire to be it may contact. The same dangerous situation may result from a malfunctioning of the parts causing a short circuit to be formed in the cigar lighter. In any case, even if no other damage results, the cigar lighter itself would be destroyed.

been solved heretofore by providing, on the inner end of the lighter,

ing drawings,

FIGURE 1 is a side view, partly in section, showing a cigar lighter of the removable igniter type with the present invention applied thereto.

FIG. 2 is a side view of Patented June 29, 1965 2 FIG. 4 is a transverse section of the circuit breaker taken on the line 44 of FIG. 3.

FIG. 5 is a longitudinal section of a modified form of circuit breaker.

As shown in FIG. 1, the quick-acting, heat-responsive circuit breaker of this invention is relatively low voltage devices, such as an electric cigar lighter, which, as shown, comprises a well or socket 10 of a supply wire connected to a source until it reaches a predetermined adapted for use with ground and the supply line, in which case the full current to the battery or other supply would be conducted through the wire 22 and the short-circuited parts causing overheating and the incident danger of fire being started.

To avoid these difficulties, the present invention provides a quick-acting, heat-responsive and current-responsive switch 21 interposed between the current supply screw In order that the clamping sleeve 16 may be applied tothe lighter after the switch 21 is the housing for the switch is made so that its maximum width is not as great as the internal diameter of the As a result, the quick-acting switch As shown in FIGS. 1 and 3, the quick-acting switch comprises an elongate bimetallic strip forming a driver i M), one end 31 of which is bent at right angles and is i secured to the output terminal 29 by spinning over the head thereof as shown, the driver 3t) extending lengthwise in the housing toward the end thereof. The 1 driver is thus in heat-conducting relation with the cigar lighter, and hence the free end 32 of the driver 36 is movable laterally, radially of the housing, when heated and cooled. The characteristic of the bimetal is such that when the driver is heated the end moves outwardly or radially away from the axis of the switch.

The switch also comprises a U-shaped current-conducting spring 33 which is located in the housing and extends substantially at right angles to the free end of the driver 3t). The spring 33 has a loop 34 with a long leg 35 and a short leg 36. The long leg 35 has a V bend forming a socket 37 to receive the free end 32 of the driver 39. The short leg 36 has a terminal portion bent at right angles with a free end 33 which fits into a V-shaped recess 39 in the end 25 of the housing, and it is on the pivotal connection formed by the free end 33 and the recess 39 that the spring 33 may oscillate. The end of the long leg 35 overlies the contact 2-6 of the input terminal and engages the same when the bimetal driver 30 is cool so as to conduct current from the input terminal 26 through itself and the driver 36 to the output terminal 29, hence to the cigar lighter.

The U-shaped spring 33 is so formed or biased that the legs 35 and 36 tend to spread apart. This would have the effect of causing the end of the leg 35 to move away from the contact 26. However, this is prevented while the driver 30 is in its cool position shown in FIGS. 1 and 3 because the bimetallic driver is long enough and stiff enough when cool to engage and hold the leg 35 against the contact 26. The leg 35 yields slightly for this purpose so as to hold the parts in desired position under all circumstances. The driver 3% is provided with a bowed portion 4-0 midway between its length as shown in FlG. 3, or a bowed portion 41 adjacent its fixed end 31 as shown in FIG. 5, but the bowed portions are not so biased when cool as to apply resilient pressure to the long leg 35 oi the spring.

The V-shaped socket 37 in the long leg of the spring is so positioned that when the bimetal strip 30' is cool, the socket will be located radially inwardly of the pivotal connection 33-39 of the spring, thus causing the long leg 35 of the spring to remain in firm contact with the current-conducting terminal 26.

When the bimetal strip 36 heats up, either because of heat conducted from the cigar lighter, or by reason of the passage of current therethrough (as in the case of a short circuit), the free end 32 of the driver 30 tends to move outwardly and carry with it the long leg 35 of the spring 33. At the same time the loop 40 or 41 expands diametricallyand this causes the free end 32 of the driver so apply increased pressure to the long leg 35 thus increasing the contact pressure thereof with the contact 26. Lateral movement of the end 32 of the driver is retarded by the spring until the bimetallic strip of the driver has been stressed to a predetermined extent which would only occur in the case of severe overheating. When this happens the force of the bimetal driver 30 will overcome the retarding resistance of the spring 33 and carry the V-shaped socket outwardly past the pivotal connection 38-3, causing the long leg 35 of the spring to move with a snap-action clear of the contact 26 a substantial distance to the position shown in FIG. 3, in broken lines, thereby avoiding any substantial or prolonged arc.

The circuit being thus opened the parts will cool off gradually due to the dissipation of the heat until eventually the bimetallic strip 30 would carry the V-shaped socket of the long leg 35 back over the pivotal connection 38-39 to reclose the circuit. It the cause for the overheating had been removed, the bimetal spring 36 will remain in the closed circuit position and the device will operate as norma. However, if the cause of the overheating still existed when the bimetal strip of the driver again overheated, the circuit would be opened and these operations would be continued until the condition was corrected or the current of the battery became exhausted.

It should be noted that in moving from the position shown in full lines in FIG. 3 to the broken line position, the long leg 35 is moved longitudinally causing a wiping action to be produced between its surface and that of the contact 26 before the spring snaps over to opencircuit position.

The contact screw 26 may have a screw-slot 26a whereby it may be turned to adjust the position of the contact end of the screw relative to the long leg 35 and to vary the response of the switch to diiierent temperatures.

Variations and modifications may be made within the scope of the claims and portions of the improvements may be used without others.

We claim:

1. As a new article of manufacture, a heat-responsive quick-acting switch having a hollow housing having end closures; an input terminal having a contact in one end of the housing; an output terminal on the other end of the housing; an elongate current conducting bimetallic driver extending lengthwise in the housing with one end fixed to the output terminal and a free end movable laterally when heated and cooled; a U-shaped current conducting spring located in the housing to extend substantially at right angles to the free end of the driver, said spring having a reverse bend, a long leg having a socket engaging the free end of the driver and the short leg having with the end of the housing on which the input contact is located, a pivotal connection on which the U- shaped spring may oscillate, the spring being biased to cause the legs thereof to continuously press outwardly, the short leg against said pivotal connection and the long leg against the free end of the driver, the free end portion of the long leg engaging the input contact when the driver is cool to complete a circuit from said input contact to said output terminal through the spring and the driver, the long leg of the spring being substantially perpendicular to the free end of the driver and the short leg of the spring being substantially aligned with the free end of the driver whereby said free end portion of the long leg makes sliding wiping engagement against said input contact with increasing pressure as the driver when heated moves laterally away from the input contact until the driver is stressed sufficiently to cause the free end of the driver to compress the free end portion of the long leg of the spring and pass over the pivotal connection thereof, whereupon the driver causes the spring to oscillate with a snap action and carry the free end of the long leg away from the input contact to open the energizing circuit.

2. A heat-responsive quick-acting switch as defined in claim 1 in which the input terminal extends through the end closure of the housing and is adjustable axially toward and from the U-shaped spring to calibrate the operation of the switch from the exterior of the housing.

3. A heat-responsive quick-acting switch as defined in claim 1, in which the free end of the driver is sutficiently long to remain engaged with the socket in the spring whereby when the driver cools to a predetermined temperature the U-shaped spring is returned to closed circuit position with the long leg in engagement with the input contact.

4. A heat-responsive quick-acting switch as defined in claim 1 in which the bimetallic driver has between its fixed end and its free end a bowed portion which when expanded diametrically in response to heating causes the free end of the driver to engage the long leg of the spring with increasing force to increase the electrical engagement prior to the movement of the spring to open-circuit position.

5. As a new article of manufacture, a heat-responsive quick-acting switch having a hollow housing having end closures; an input terminal having a contact in one end of the housing; an output terminal on the other end of the housing; an elongate current conducting bimetallic driver extending lengthwise in the housing with one end fixed to the output terminal and a free end movable laterally when heated and cooled; a U-shaped current conducting spring located in the housing to extend substantially at right angles to the free end of the driver, said cause the legs thereof to continuously press outwardly, the short leg against said pivotal connection and the long leg against the free end of the driver, the free end portion or" the long leg engaging the input contact when the driver is cool to complete a circuit from said input contact to said output terminal through the spring and the driver, the long leg of the spring being substantially perpendicular to the free end of the driver and the short leg of the spring being substantially aligned with the free end of the driver whereby said free end portion of the long leg makes sliding wiping engagement against said input contact with increasing pressure as the driver when heated moves laterally away from the input contact until the driver is stressed sufficiently to cause the free end of the driver to compress the free end portion of the long leg of the spring and pass over the pivotal connection thereof, whereupon the driver causes the spring to oslong leg away from the input contact to open the energizing circuit, the bimetallic driver having a'bowed portion between its free end which engages the spring and its fixed end a portion which causes its free end to engage the spring and force the same with increasing pressure against the input contact as the bimetallic driver is being heated.

6. A heat-responsive quick-acting switch as defined in claim 5 in which the input terminal is a screw threaded in the outer end closure and is adjustable by rotation to move its contact end closer to or farther from the U- shaped spring to calibrate the operation of the switch.

References Cited by the Examiner UNITED STATES PATENTS BERNARD A. GILHEANY, Primary Examiner. 

1. AS A NEW ARTICLE OF MANUFACTURE, A HEAT-RESPONSIVE QUICK-ACTING SWITCH HAVING A HOLLOW HOUSING HAVING END CLOSURES; AN INPUT TERMINAL HAVING A CONTACT IN ONE END OF THE HOUSING; AN OUTPUT TERMINAL ON THE OTHER END OF THE HOUSING; AN ELONGATE CURRENT CONDUCTING BIMETALLIC DRIVER EXTENDING LENGTHWISE IN THE HOUSING WITH ONE END FIXED TO THE OUTPUT TERMINAL AND A FREE END MOVABLE LATERALLY WHEN HEATED AND COOLED; A U-SHAPED CURRENT CONDUCTING SPRING LOCATED IN THE HOUSING TO EXTEND SUBSTANTIALLY AT RIGHT ANGLES TO THE FREE END OF THE DRIVER, SAID SPRING HAVING A REVERSE BEND, A LONG LEG HAVING A SOCKET ENGAGING THE FREE END OF THE DRIVER AND THE SHORT LEG HAVING WITH THE END OF THE HOUSING ON WHICH THE INPUT CONTACT IS LOCATED, A PIVOTAL CONNECTION ON WHICH THE USHAPED SPRING MAY OSCILLATE, THE SPRING BEING BIASED TO CAUSE THE LEGS THEREOF TO CONTINUOUSLY PRESS OUTWARDLY, THE SHORT LEG AGAINST SAID PIVOTAL CONNECTION AND THE LONG LEG AGAINST THE FREE END OF THE DRIVER, THE FREE END PORTION OF THE LONG LEG ENGAGING THE INPUT CONTACT WHEN THE DRIVER IS COOL TO COMPLETE A CIRCUIT FROM SAID INPUT CONTACT TO SAID OUTPUT TERMINAL THROUGH THE SPRING AND AND DRIVER, THE LONG LEG OF THE SPRING BEING SUBSTANTIALLY PERPENDICULAR TO THE FREE END OF THE DRIVER AND THE SHORT LEG OF THE SPRING BEING SUBSTANTIALLY ALIGNED WITH THE FREE END OF THE DRIVER WHEREBY SAID FREE END PORTION OF THE LONG LEG MAKES SLIDING WIPING ENGAGEMENT AGAINST SAID INPUT CONTACT WITH INCREASING PRESSURE AS THE DRIVER WHEN HEATED MOVES LATERALLY AWAY FROM THE INPUT CONTACT UNTIL THE DRIVER IS STRESSED SUFFICIENTLY TO CAUSE THE FREE END OF THE DRIVER TO COMPRESS THE FREE END PORTION OF THE LONG LEG OF THE SPRING AND PASS OVER THE PIVOTAL CONNECTION THEREOF, WHEREUPON THE DRIVER CAUSES THE SPRING TO OSCILLATE WITH A SNAP ACTION AND CARRY THE FREE END OF THE LONG LEG AWAY FROM THE INPUT CONTACT TO OPEN THE ENERGIZING CIRCUIT. 